Source Code for Module dns.rcode

  1  # Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license 
  2   
  3  # Copyright (C) 2001-2017 Nominum, Inc. 
  4  # 
  5  # Permission to use, copy, modify, and distribute this software and its 
  6  # documentation for any purpose with or without fee is hereby granted, 
  7  # provided that the above copyright notice and this permission notice 
  8  # appear in all copies. 
  9  # 
 10  # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES 
 11  # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 
 12  # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR 
 13  # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 
 14  # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 
 15  # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 
 16  # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 
 17   
 18  """DNS Result Codes.""" 
 19   
 20  import dns.exception 
 21  from ._compat import long 
 22   
 23  #: No error 
 24  NOERROR = 0 
 25  #: Form error 
 26  FORMERR = 1 
 27  #: Server failure 
 28  SERVFAIL = 2 
 29  #: Name does not exist ("Name Error" in RFC 1025 terminology). 
 30  NXDOMAIN = 3 
 31  #: Not implemented 
 32  NOTIMP = 4 
 33  #: Refused 
 34  REFUSED = 5 
 35  #: Name exists. 
 36  YXDOMAIN = 6 
 37  #: RRset exists. 
 38  YXRRSET = 7 
 39  #: RRset does not exist. 
 40  NXRRSET = 8 
 41  #: Not authoritative. 
 42  NOTAUTH = 9 
 43  #: Name not in zone. 
 44  NOTZONE = 10 
 45  #: Bad EDNS version. 
 46  BADVERS = 16 
 47   
 48  _by_text = { 
 49      'NOERROR': NOERROR, 
 50      'FORMERR': FORMERR, 
 51      'SERVFAIL': SERVFAIL, 
 52      'NXDOMAIN': NXDOMAIN, 
 53      'NOTIMP': NOTIMP, 
 54      'REFUSED': REFUSED, 
 55      'YXDOMAIN': YXDOMAIN, 
 56      'YXRRSET': YXRRSET, 
 57      'NXRRSET': NXRRSET, 
 58      'NOTAUTH': NOTAUTH, 
 59      'NOTZONE': NOTZONE, 
 60      'BADVERS': BADVERS 
 61  } 
 62   
 63  # We construct the inverse mapping programmatically to ensure that we 
 64  # cannot make any mistakes (e.g. omissions, cut-and-paste errors) that 
 65  # would cause the mapping not to be a true inverse. 
 66   
 67  _by_value = {y: x for x, y in _by_text.items()} 
 68   
 69   
 70 -class UnknownRcode(dns.exception.DNSException): 
 71      """A DNS rcode is unknown.""" 
 72   
 73   
 74 -def from_text(text): 
 75      """Convert text into an rcode. 
 76   
 77      *text*, a ``text``, the textual rcode or an integer in textual form. 
 78   
 79      Raises ``dns.rcode.UnknownRcode`` if the rcode mnemonic is unknown. 
 80   
 81      Returns an ``int``. 
 82      """ 
 83   
 84      if text.isdigit(): 
 85          v = int(text) 
 86          if v >= 0 and v <= 4095: 
 87              return v 
 88      v = _by_text.get(text.upper()) 
 89      if v is None: 
 90          raise UnknownRcode 
 91      return v 
 92   
 93   
 94 -def from_flags(flags, ednsflags): 
 95      """Return the rcode value encoded by flags and ednsflags. 
 96   
 97      *flags*, an ``int``, the DNS flags field. 
 98   
 99      *ednsflags*, an ``int``, the EDNS flags field. 
100   
101      Raises ``ValueError`` if rcode is < 0 or > 4095 
102   
103      Returns an ``int``. 
104      """ 
105   
106      value = (flags & 0x000f) | ((ednsflags >> 20) & 0xff0) 
107      if value < 0 or value > 4095: 
108          raise ValueError('rcode must be >= 0 and <= 4095') 
109      return value 
110   
111   
112 -def to_flags(value): 
113      """Return a (flags, ednsflags) tuple which encodes the rcode. 
114   
115      *value*, an ``int``, the rcode. 
116   
117      Raises ``ValueError`` if rcode is < 0 or > 4095. 
118   
119      Returns an ``(int, int)`` tuple. 
120      """ 
121   
122      if value < 0 or value > 4095: 
123          raise ValueError('rcode must be >= 0 and <= 4095') 
124      v = value & 0xf 
125      ev = long(value & 0xff0) << 20 
126      return (v, ev) 
127   
128   
129 -def to_text(value): 
130      """Convert rcode into text. 
131   
132      *value*, and ``int``, the rcode. 
133   
134      Raises ``ValueError`` if rcode is < 0 or > 4095. 
135   
136      Returns a ``text``. 
137      """ 
138   
139      if value < 0 or value > 4095: 
140          raise ValueError('rcode must be >= 0 and <= 4095') 
141      text = _by_value.get(value) 
142      if text is None: 
143          text = str(value) 
144      return text 
145